This invention is directed to an ink ribbon cassette and, in particular, to an ink ribbon cassette for a franking machine or the like that controls the braking pressure on the take-off spool for the ink ribbon as the spool decreases in diameter.
An ink ribbon cassette for printing, and in particular, for franking machines are known in the prior art. These cassettes include a housing, a take-up core rotatably mounted in the housing, an ink ribbon spool wound up on a take-off core rotatably mounted in the housing and a brake component. The front end of the ribbon is fastened to the take-up core. The take-off core is arranged in the housing so as to be rotatable with a ribbon spool. The ribbon is drawn from the spool by way of ribbon guide components on two projecting housing legs. A spring generating a constant braking moment presses against the take-off core. As a result thereof, the ribbon tension increases with the decreasing spool diameter causing malfunction.
Accordingly, it is desired to provide an improved ink ribbon cassette which controls the braking force imparted on the ink ribbon spool as the ink ribbon spool decreases in diameter.